1. Field of the Invention
The present invention relates to electric power generation for vehicles. More particularly, the present invention relates to wind turbines mounted on moving vehicles for converting the wind energy into electricity for storage in a battery system or use by the vehicle.
2. Description of the Related Art
Wind turbines are typically mounted on wind towers in areas known to have high wind velocity. Various configurations of wind turbines are designed to convert wind energy into electrical power for use in homes and industries.
The greatest challenge with wind turbines as a reliable source of energy is that they depend on the quantity and quality of the wind. Depending on the design, wind speed must maintain a certain minimum velocity to overcome friction of moving parts. Even in the best geographical areas, average wind speed is only in the range of 18 to 47 kph. To justify the projects, and generate adequate return on investment, the sizes of wind turbines are usually very large, with rotor diameter in the range of 40 to 50 meters. Typical rotor speed is between 20 and 50 rpm, which must be increased, through a gearbox, to between 1,000 and 1,500 rpm, which is required for most types of electric generators.
Despite the above challenges, interest remains very high around the world to harvest this clean, free, and inexhaustible energy source, i.e., wind power.
Transportation vehicles such as automobiles, trucks, and trains are usually moving at moderate to high speed on an open road. This movement generates an approximately opposite and equal head wind speed relative to the vehicle. This wind causes “wind drag,” and is usually detrimental to the overall efficiency of the vehicle.
Due to air pollution and noise concerns, electric and/or hybrid electric vehicles are gaining popularity in states such as California and New York, as well as in Europe and Japan.
The advantages of electric vehicles include low cost per kilometer of driving distance, no “engine” noise, and recovery of energy (battery system is recharged) through regenerative braking. The greatest challenges for such electric vehicles include the fact that the battery system must be recharged when battery system power is exhausted, and the driving range is limited, due to limited storage capacity in its battery system. Battery system power is spent very quickly when the vehicle is moving predominately forward, without slowing or braking to allow for recharge of the battery system through regenerative braking.
In hybrid electric vehicles, the vehicle range is extended by adding a small gasoline or diesel engine. The engine is used mainly as a backup power source to recharge the battery system when the charge is low, or when the vehicle needs a power boost to climb a long hill, or pass another vehicle. The advantages of this system include low pollutant emissions, low cost per kilometer of driving distance, low noise, the recovery of energy through regenerative braking, and unlimited range from a charging station as long as the vehicle is refueled with gas or diesel fuel.
In today's vehicles, including electric, hybrid electric, and convention fossil fuel-powered vehicles, the faster the vehicle is moving, the more wind resistance it has to overcome. The prevailing wind force is therefore detrimental to the efficiency of the moving vehicles.
There is a need to harness and convert the energy lost to detrimental wind drag into a beneficial source of energy. There is also a need to provide an apparatus such as a wind turbine mounted on the moving vehicle to capture this otherwise wasted energy and convert it into a useful source of energy.
U.S. Design Pat. No. 374,656, issued Oct. 15, 1996, to Richardson, illustrates a car top wind generator.
U.S. Pat. No. 3,876,925, issued Apr. 8, 1975, to Stoeckert, describes a wind turbine affixed to the roof of an electric car and designed such that the force of prevalent air currents is converted into electricity from any direction, whether the car is in motion or not.
U.S. Pat. No. 4,168,759, issued Sep. 25, 1989, to Hull, deceased, et al., and U.S. Pat. No. 5,746,283, issued May 5, 1998, to Brighton, each describe contouring of the rooftop wind turbine housing to insure smooth airflow over the electric vehicle.
U.S. Pat. No. 5,986,429, issued Nov. 16, 1999, to Mula, Jr., and U.S. Pat. No. 6,138,781, issued Oct. 31, 2000, to Hakala, describe wind-powered systems for vehicles which are positioned longitudinally along the frame structure of the electric vehicle, thus, minimizing the drag effect associated with the wind tunnel.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a wind energy capturing device for moving vehicles solving the aforementioned problems is desired.